Science explained with humor, analogy, and pop culture. (Because sometimes you just wanna understand a thing…)

The Plates That Time Forgot

Isosceles, Equilateral, and Scalene. Yawn. Like people at a party you know youll never see again.now were talkin sexy triangles

by chelsea schuyler

Can we just talk for a second of the rockindom of the Stegosaurus? Those plates, what’s going on there?

The boxer brief: The history of our impressions of the Stegosaurus is, as so many human trains of thought, somewhat humiliating. Stegosaurus means “roof lizard” because we used to think the plates laid flat over its back like roof tiles. We now believe they stood upright (in effect raising the roof, and maintaining name integrity).

Instead of lummox-y monsters melting in the swamp of their own claymation, we now see a dignified, agile creature that might actually stand a chance against Jason AND the Argonauats. Stegosaurus had large deltoid (yeah I said deltoid) muscles for quick side-stepping, pivoting on its back legs and swinging a flexible tail that held those famous spikes.

“Now this end is called the thagomizer, after the late Thag Simmons.”

The tailspikes are called the “thagomizer” which is the awesomest name ever, and I kid you not, was coined by the GENIUS Gary Larson in a 1982 Far Side strip. It stuck, and is now official paleontology slang.

Paleontologist Robert Bakker thinks the Steg was perfectly built to support a tripod stance, rearing up on its back legs and tail, kangaroo style. Being tall gets you a lot more leaves on those pesky conifers of the day (and as we all know, short people got no reason to live). The Stegosaurus body worked a lot like a crane–the hind legs and heavy tail like the base of the crane (where the construction dude sits) and the head and forelegs like the …picky uppy, neck part of the crane. I don’t know, I don’t do cranes. And there are virtually no pictures of the Stegosaurus doing this on the net, it’s very aggravating, but it’s kinda like this:

only not as lame

This video, though painful, as nearly all modern media portrayals of dinosaurs are (save Jurassic Park), is actually a fairly well done depiction of the Stegosaurus according to modern theory. Tripod eating habits, high tailin it, and pivoting on the back legs to quickly shift their position. Also, extensive footage of the Stegosaurus naturally blanketed in the warm comforts of John Goodman.

So, about those triangles, what the hell? They are called osteoderms, bone-like structures of the skin, basically giant scales. What were they for? As usual, we don’t know. Incoming Scientific Speculation alert!!

1) sexual attraction. the somewhat disappointing but relevant (cop-out) theory. Not something you can really go farther with when dealing with the extinct. Stegosaurus mating–there’s only guessing as to how that worked. ow. Paleontologists would kill to get a “handle” on Stegosaurus “love triangles,” which has always been a “prickly” subject.

2) armor. sure, anyone best be keepin dey munchin face outta that whole area. So yeah, that could be intimidating to a predator, but the armor theory has fallen quite out of favor. Their backs just don’t need the extra defense. The vertebra of a Stegosaurus has massive spines thought to provide purchase for extra muscle to support that whole crane position. Note the vertebral spines in comparison to ours:

steg: spineriffic boneshuman: spine denied

In The Dinosaur Heresies Robert Bakker claims that “Any Allosaurus unwise enough to bite into that ridge would have broken off its teeth without inflicting significant damage.” Breaking teeth off. I don’t why that’s so amusing to me. can we get the sound fx guy on that?

Anyway, Bakker thinks the plates’ angles were adjustable, able to swing out to the sides a bit to better stave off a predator from its vulnerable flanks. This wouldn’t work on say, a crocodile (who have the same kind of back, with little mini plates), as their plates are firmly lodged width-wise in the tough skin. A Stegosaurus plates only just sits atop that skin, and could have left room for muscle manipulation.

3) thermoregulation. You know an elephant’s giant ears? The thin skin is filled with blood vessels that can absorb heat from the sun or cool off from a breeze or by fanning. Some scientists think the plates serve the same function, as they do have large blood vessels running through them. But if this is the case, some species got the short end of the stick, having only thin spines instead of plates. Not enough surface area to do much . Hmm

Oh to know what we’ll think in another 100 years! Meanwhile, the little people have their fun. Colorado has wisely named the Stegosaurus the state fossil. Wait, we have state fossils?? What’s Oregon’s?

Oregons lame state fossil. Made in China.

The Dawn Redwood. A friggin tree, that A) still exists and B) is not even native! They thought it was extinct but then they found a grove in China, Bogarted the seeds and now it’s all over the country. Nothing against trees or anything, but seriously? To see if your state is as lame as ours, check out this website.

Meanwhile some sewer guys found a dinosaur fossil in D.C. and named it Capitalsaurus. sigh. And then the government had to go all Declaration on it and created the Official Dinosaur Designation Act of 1998, of which Section 4 states: “This act shall have no fiscal impact.” Really? That has nothing to do with, it’s not even, we spend time on this? I mean there’s even a part where they specify that if the mayor vetoes it the Council will override and OH MY GOD PEOPLE

This blog shall have no pituitary impact.

This blog shall have no pituitary impact.

Remember (the 80s) Geometry? Being introduced to Equilateral, Isosceles, and Scalene triangles like people at a party you know you’ll never meet again? You mingle long enough to wonder if Isosceles got regularly beat up by Hercules, and why Scalene is so obtuse. (You’re so obtuse.) How are you supposed to focus?? The teacher says “triangle” and naturally your first thought was those Stegosaurus plates called osteoderms, bonelike structures like giant scales shaped like triangles. naturally.

Clearly the bizarre plates on the bus-sized beast of the prehistoric bad lands are of upmost importance. I shall fill in the lost unit of class that we all could have benefited from. Cuz I mean, really, what were those mysterious triangular plates for anyway?

The boxer brief: The history of our impressions of the Stegosaurus is, as so many human trains of thought, somewhat humiliating. But that’s okay, you gotta expect some misjudgments when all they had was a few bones to play with. Stegosaurus means “roof lizard” because we used to think the plates laid flat over its back like roof tiles. We now believe they stood upright (in effect raising the roof, and maintaining name integrity). We fixed that pretty quick, others were not so lucky. Figure one shows old school Stegosaurus; Figure two, new school:

Old school: Lumbering. Tail dragging. Low feeders.

New school. Nimble (ish). Tail raised high off the ground. High feeders. Now we realize that Stegosaurus had large deltoid muscles for quick side-stepping, pivoting on its back legs and swinging a flexible tail that held those 4 (sometimes 8!) famous spikes. The tailspikes are called the “thagomizer” which is the awesomest name ever, and I kid you not, was coined by the GENIUS Gary Larson in a 1982 Far Side strip. It stuck, and is now official paleontology slang.

Anyway, where were we? Tail dragging. Not so much, although I cherish the old stop-motion movies, Stegosaurus walked with its tail held high off the ground. If it makes you feel any better though, Robert Bakker thinks the Steg was perfectly built to support a tripod stance, rearing up on its back legs and tail, kangaroo style. Which brings me to High Feeding, rearing up gets you a lot more leaves. The Stegosaurus body worked a lot like a crane if you can picture that. The hind legs and heavy tail like the base of the crane (where the construction dude sits) and the head and forelegs like the …picky uppy, neck part of the crane. I don’t know, I don’t do cranes. And there are virtually no pictures of the Stegosaurus doing this on the net, it’s very aggravating, but it’s kinda like this:

What were these weird plates for? As usual, we don’t know. Incoming Scientific Speculation alert!!

1) sexual attraction. the somewhat disappointing but relevant (cop-out) theory. Not something you can really go farther with when dealing with the extinct. Stegosaurus mating, there’s only guessing as to how that worked. ow. Paleontologists would kill to get a “handle” on Stegosaurus “love triangles,” which has always been a “prickly” subject.

2) armor. okay, obvious, and sure, anyone best be keepin dey munchin face outta that whole area. So yeah, that could be intimidating to a predator, but this theory has fallen quite out of favor. Thedoes the back need such a defense? The vertebra of a Stegosaurus has massive spines (thought to provide purchase for extra muscle to support that whole crane position) Note the vertebral spines in comparison to our spine:

In The Dinosaur Heresies (which is where much of this blog is coming from) Robert Bakker claims that “Any Allosaurus unwise enough to bite into that ridge would have broken off its teeth without inflicting significant damage.” Breaking teeth off. I don’t why that’s so amusing to me. can we get the sound fx guy on that?

So anyway, you don’t put your armor over your strongest parts. Bakker believes that the plates’ angle could be controlled by muscle, enabling them to swing somewhat from side to side. Angling plates toward an attacker would lend some protection to the vulnerable flanks and give a more dynamic defense.

3) thermoregulation. Dead end blood vessels running through the plates led some scientists to wonder if they could be used to absorb heat from the sun, or to cool off from a breeze. But if that’s true some Stegosaurus species got the short end of the stick, having only thin spins instead of plates. Not enough surface area . Hmm

This video, though painful, as nearly all modern media portrayals of dinosaurs are (save the saintly Jurassic Park), is actually a fairly well done depiction of the Stegosaurus according to modern theory. Tripod eating habits, high tailin it, and pivoting on the back legs to quickly shift their position in fast defensive postures. And blanketed in the warm comforts of John Goodman.

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4 comments

1: Excellent Randy Newman reference. Can you somehow work in “Sigmund Freud’s Impersonation Of Albert Einstein In America” in the next one??

B: I know, right?! Trees are like, Lamest Ever! Turns out the state I live in has a goddamn tree for an official fossil also. The Palmwood. Even thought we already *have* a stupid “state tree” also! And they’re different trees! What, like we need TWO DIFFERENT TREES floating around on official state government stationary?! Why couldn’t it be something bitching like a pterodactyl? Or a dragon? That would be rad.

**Update**

Actually, a brief internet search confirms the Palmwood is not a tree as I had assumed, but rather “a Luxury Boutique Inn perched on the ridge of a four acre estate overlooking the peaceful Moloaa’ Valley located on Kauai’s northeastern coastline.” So our state fossil is a hotel we stole from Hawaii, which is kind of cool in its own right.

At least the Palmwood is extinct! Instead of woops, found it in China (it’s actually part of the H which isn’t fair). Plus legend (the sacred legend of Bernardine fine jewlery’s website) has it that gemstones of petrofied Palmwood “Removes petty annoyances.” Like hotels in Hawaii!

We are surrounded by coolness yet fail so severely. Let’s see, WA has a mammoth, ID has a horse, CA has a saber-toothed freakin cat and we, have, a, tree? A feathery one at that. What, were fossilized pansies taken? (Just checked, nope!) All fossils are cool, but c’mon!

If I ever get me a crane, I’m adding a thagomizer straight away! See, how could you not take Larson seriously? He has scientific credibility (which of course we already knew).